Process of treating metalliferous ores.



UNITED STATES PATENT OFFICE.

FRANKLIN R. CARPENTER, OF DENVER, COLORADO, ASSIGNOR TO THE AMERICANIRON AND STEEL ALLOYS COMPANY, OF DENVER, COLORADO, A CORPORATION OFCOLORADO.

PROCESS OF TREATING METALLIFEROUS ORES.

Specification of Letters Patent.

Patented Nov. 24, 1908.

To all whom it may concern:

Be it known that I, FRANKLIN R. CARPEN- 'IER, a citizen of the UnitedStates of America, residing in Denver, in the county of Denver and Stateof Colorado, have invented a new and useful Process of TreatingMetalliferous Ores, of which the following is a specification.

There exist many large deposits of ores mainly copper ores, and gold andsilver ores having a gangue that is largely silica or silicates.Examples of such copper ores are found in the so called monzonitedeposits of Nevada and Utah, in which the copper is mainly in the sulfidform but is so finely disseminated that the losses by mechanicalconcentration are very great and owing to the vast amount of basic fluxand the fuel required it does not pay to smelt these ores direct.

Examples of the gold ores which, for similar reasons can neither besmelted nor concentrated, are the silicious ores of the Black Hills,South Dakota, and certain quartz-like ores in Nevada. I have discovereda method of treatment for these ores in which they are separated withoutfusing the gangue to effect a separation.

In the old \Velch method of copper smelting, silicious copper ores weretreated by a process of soaking, but this was really a smelting processin which slag enough was made to float off the unfused quartz fragments,without which slag it was impossible to skim the furnace. It wasmoreover a very costly process owing to the large amounts of fuel used.One might pass crushed ore over a bed of molten matte or metal andgradually soak out the values, but unless sufficient slag was formed tofloat or wash out the unaltered rock, the furnace could not beskimmed,except at a great loss of the underlying matte or metal.

In carrying out my invention I may conveniently use a reverberatoryfurnace which may be fired in the ordinary way. The furnace hearth maybe of any desired shape. A circular form with the ore fed near thecenter and gradually worked outwardly would give good results, but forthe purpose of illustrating my process I will assume an ordinaryreverberatory smelting furnace of the WVelch type fired in the usualway, such as is used by all smelters where copper ores are smelted bythe reverberatory process.

Upon the hearth of this furnace there is provided a fixed bath which maybe a bed of molten matte, either copper or iron, or a mixture of the twometals, or a bed of lead or other metal, the specific gravity of which,

however, should be less than that of the ore, but greater than that ofthe gangue. Upon this bed I place crushed ore of earthy or siliciousgangue carrying metals of value, which latter are separated from thegangue by contact with the molten matte or metal, and without actuallyfusing the ore, no flux being used and no slag being formed and arelatively small amount of fuel for heating being employed. In the old\Velch process referred to, enormous heat was requlred, a flux wasusually employed and the ore was smelted producing a slag which was ofgreater specific gravity than the silicious ore so that this ore did notcome in contact with the bath but floated on top of the slag.

In my process the metallic values are either dissolved in the moltenbath or such as are of greater specific gravity than the bath will sinkthrough it, but as this bath is of greater specific gravity than thegangue, the latter will be neither dissolved in, nor sink through thebath, but will merely float on it and can be readily removed in wellknown ways.

It is sometimes desirable with certain ores to provide means for morereadily skimming the furnace so as to avoid loss of matte or metal andit is also desirable in some cases to prevent any oxidizing actioneither of the ore or of the bath. In my application for Patent No.325,546, filed July 10, 1906, I have described a method of treating oresin which a medium is provided which does not to any extent combine withthe ore 01' with the bath, but allows the leaching, separating ofvalues, and the skimming of the furnace without actually fusing earthyportions ofthe ore. This substance or medium is fusible at comparativelylow temperature and acts partially as a mechanical concentrating medium,but mainly as a medium that can be used for washing out and floating offthe freed rock. This medium is of less specific gravity than the bathand is neutral to it as well as to the ore. According to the inventionclaimed in the present application, which covers a method of treatmentsuitable for some ores, no such medium interposed between the ore andthe bath is employed.

When I speak of the metals being dissolved in or passing through thebath l, of course, intend to include compounds of the metals such assulfids. The method-of treatment may be employed with mixed ores. Suchmetals or compounds thereof as are soluble in the bath or are of greaterspecific gravity than the bath will be separated from the ore, whilethose which are not soluble in the bath, or are of less specific gravitythan the bath, will remain on the surface thereof with the gangue. Theunderlying dissolving and separating bath may be composed of suitablemetal or matte, or it may be a silicate of definite specific gravity, orin some cases it may consist of sulfur. Other substances suitable forthe same purpose will readily suggest themselves to those skilled inmetallurgical matters.

Another characteristic of the bath is that while it is solid at ordinarytemperatures, it is fusible at a comparatively low temperature.

My treatment of the orcs may be considered a concentrating treatment andmay take the place of concentrating processes in which water is used,where water is scarce or not available.

In the specification and claims the term ore includes all theconstituents of the ore 6., both the metallic values and the gangue.

I claim as my invention 1. The process of treating ores without the useof a flux and without producing a slag, which consists in feeding theore onto the top of a molten bath of less specific gravity than the oreand of greater specific gravity than the gangue of such ore.

2. The process of treating ores by separating the metallic values fromgangue without producing a slag and without the use of a Hun, whichconsists in subjecting the native ore to a molten bath of less specificgravity than the ore and of greater specific gravity than the gangue ofsuch ore.

The process of treating ores for separating metallic values from thegangue without the use of :1 flux and without producing a slag, whichconsists in feeding the ore onto the top of a molten bath of lessspecific gravity than the metallic constituents within the ore but ofgreater specific gravity than the separated gangue.

4. The process of treating ores without the use of a flux and withoutproducing a slag, which consists in feeding the ore onto the top of abath consisting of a substance solid. at ordinary temperatures but fluidwhen heated and the specific gravity of which is less than that of theore but greater than that of the gangue of such ore.

In testimony whereof, I have hereunto subscribed my name.

FRANKLIN R. CARPENTER.

Witnesses ARTHUR IIOXVEGARPENTER, Gnarzsron Hown CARPENTER.

